THE CHEMISTRY AND PHYSICS OF THE CELL 25 



albumin ; probably cell albumin is most closely related to the 

 last, and what has been described as cell albumin is perhaps in 

 many cases but serum albumin that has been imperfectly 

 removed. 



Globulins also occur in all cells, but in small amounts in 

 most animal cells except the muscles, whose chief proteids 

 belong to this or a closely related group. The globulins are 

 quite similar to the albumins, so that there is really no sharp 

 line between the two groups. Their insolubility in water 

 separates them from albumins, and their solubility in dilute 

 neutral salt solutions from the more complex proteids. An 

 important feature of the globulins is the low temperature at 

 which they coagulate some so low that Halliburton l believes it 

 possible that they may be coagulated within the cells during 

 high fevers. 



Hammarsten has long maintained that simple proteids form 

 a relatively insignificant part of the cytoplasm, in opposition to 

 the once-prevalent view that the nucleo-proteids were limited to 

 the nucleus, and that the cytoplasm was chiefly albumin and 

 globulin. The general trend of opinion as influenced by the 

 results of researches has been favorable to his contentions, and 

 we shall probably not be far wrong in accepting his statement 

 that " The chief mass of the protein substances of the cells 

 does not consist of proteids in the ordinary sense, but consists 

 of more complex phosphorized bodies, and that the globulins 

 and albumins are to be considered as nutritive materials for the 

 cells or as destructive products in the chemical transformation 

 of the protoplasm/' 



Nucleo-proteids are probably the most important constituents 

 of the cell, both in quantity and in relation to cell activity. 

 The enzymes seem to be nucleo-proteids, or at least they are 

 intimately associated with them. (See further discussion under 

 the subject of enzymes.) In structure the nucleo-proteids are 

 very complex, as indicated by the different products yielded on 

 hydrolytic cleavage of the molecule. Furthermore, there are 

 many varieties, depending both upon the nature and proportions 

 of the component parts. They may be described as consisting 

 of two primary constituents (1) nucleic acid and (2) a proteid 

 body, in chemical combination with each other like a salt. In 

 the chro matin structures of the nucleus the proportion of proteid 

 in the nucleo-proteid is small, so that these bodies have a 

 strongly acid character, as indicated by their affinity for basic 



1 Halliburton and Mott, Archives of Neurology, 1903 (2), 727 ; also see 

 Halliburton' s " Chemistry of Muscle and Nerve. " 



